前言
FastAPI 服务是通过 uvicorn 来提供的，日志都是 uvicorn 里配置的。
官方文档地址：https://www.uvicorn.org/settings/#logging
uvicorn 的 logging 日志
我们可以通过 uvicorn.run() 方式启动服务
uvicorn.run("example:app", port=5000, reload=True, access_log=False)于是可以加一些启动参数，与logging 日志相关的几个参数：
** --log-config＜path＞ 日志配置文件。**
选项：dictConfig（）格式：.json、.yaml。任何其他格式都将使用fileConfig（）处理。
设置formatters.default.use_colors和formatters.access.use_cors值以覆盖自动检测的行为。
如果您希望在日志配置中使用YAML文件，则需要将PyYAML作为项目的依赖项，或者安装带有[标准]可选附加功能的uvicorn。
--log-level＜str＞ 置日志级别。
选项：'critical', 'error', 'warning', 'info', 'debug', 'trace'。默认值：'info'。
--no-access-log
--use-colors/--no-use-colorss-启用/禁用日志记录的彩色格式，如果未设置此选项，则会自动检测到。如果使用--log-config CLI选项，则会忽略此选项。
启动服务
当我们启动服务，服务接口的时候，看到的日志是没有显示时间格式的
from fastapi import FastAPI
app = FastAPI()
@app.get("/demo/")
async def create_item():
return {"demo": "hello world"}
if __name__ == "__main__":
import uvicorn
uvicorn.run(
app='main:app',
host="127.0.0.1",
reload=True,
port=8000,
)运行日志
INFO: Will watch for changes in these directories: ['D:\\code\\fast_project\\xxx']
INFO: Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO: Started reloader process [10924] using StatReload
INFO: Started server process [5708]
INFO: Waiting for application startup.
INFO: Application startup complete.
INFO: 127.0.0.1:5161 - "GET / HTTP/1.1" 404 Not Found
INFO: 127.0.0.1:5161 - "GET /docs HTTP/1.1" 200 OK
INFO: 127.0.0.1:5161 - "GET /demo HTTP/1.1" 307 Temporary Redirect
INFO: 127.0.0.1:5161 - "GET /demo/ HTTP/1.1" 200 OK那么这些日志是从哪来的，又如何修改日志的默认格式呢？
LOGGING_CONFIG 日志默认格式
LOGGING_CONFIG 是uvicorn默认的日志配置
from uvicorn.config import LOGGING_CONFIG找到源码里面的配置内容如下
LOGGING_CONFIG: Dict[str, Any] = {
"version": 1,
"disable_existing_loggers": False,
"formatters": {
"default": {
"()": "uvicorn.logging.DefaultFormatter",
"fmt": "%(levelprefix)s %(message)s",
"use_colors": None,
},
"access": {
"()": "uvicorn.logging.AccessFormatter",
"fmt": '%(levelprefix)s %(client_addr)s - "%(request_line)s" %(status_code)s', # noqa: E501
},
},
"handlers": {
"default": {
"formatter": "default",
"class": "logging.StreamHandler",
"stream": "ext://sys.stderr",
},
"access": {
"formatter": "access",
"class": "logging.StreamHandler",
"stream": "ext://sys.stdout",
},
},
"loggers": {
"uvicorn": {"handlers": ["default"], "level": "INFO", "propagate": False},
"uvicorn.error": {"level": "INFO"},
"uvicorn.access": {"handlers": ["access"], "level": "INFO", "propagate": False},
},
}我们可以通过修改"formatters"默认的日志格式，来控制日志输出的格式
from fastapi import FastAPI
from uvicorn.config import LOGGING_CONFIG
LOGGING_CONFIG["formatters"]["default"]["fmt"] = "%(asctime)s - %(levelprefix)s %(message)s"
app = FastAPI()
······于是就可以看到启动的日志，前面加上了时间"%(asctime)s"
2024-01-16 09:49:04,408 - INFO: Will watch for changes in these directories: ['D:\\code\\fast_project\\xxx']
2024-01-16 09:49:04,408 - INFO: Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
2024-01-16 09:49:04,408 - INFO: Started reloader process [9124] using StatReload
2024-01-16 09:49:04,924 - INFO: Started server process [11020]
2024-01-16 09:49:04,924 - INFO: Waiting for application startup.
2024-01-16 09:49:04,924 - INFO: Application startup complete.访问 http 接口的日志通过修改"access"格式来控制
from fastapi import FastAPI
from uvicorn.config import LOGGING_CONFIG
LOGGING_CONFIG["formatters"]["default"]["fmt"] = "%(asctime)s - %(levelprefix)s %(message)s"
LOGGING_CONFIG["formatters"]["access"]["fmt"] = "%(asctime)s - %(levelprefix)s %(client_addr)s - \"%(request_line)s\" %(status_code)s"
app = FastAPI()
log_config 配置文件
前面是通过修改LOGGING_CONFIG 默认的参数来配置日志，我们也可以把配置文件单独写到一个uvicorn_config.json文件，加载本地配置文件覆盖默认的LOGGING_CONFIG
uvicorn_config.json
{
"version": 1,
"disable_existing_loggers": false,
"formatters": {
"default": {
"()": "uvicorn.logging.DefaultFormatter",
"fmt": "%(asctime)s - %(levelprefix)s %(message)s",
"use_colors": null
},
"access": {
"()": "uvicorn.logging.AccessFormatter",
"fmt": "%(asctime)s - %(levelprefix)s %(client_addr)s - \"%(request_line)s\" %(status_code)s"
}
},
"handlers": {
"default": {
"formatter": "default",
"class": "logging.StreamHandler",
"stream": "ext://sys.stderr"
},
"access": {
"formatter": "access",
"class": "logging.StreamHandler",
"stream": "ext://sys.stdout"
}
},
"loggers": {
"uvicorn": {
"handlers": [
"default"
],
"level": "INFO"
},
"uvicorn.error": {
"level": "INFO"
},
"uvicorn.access": {
"handlers": [
"access"
],
"level": "INFO",
"propagate": false
}
}
}启动时导入配置文件
from fastapi import FastAPI
app = FastAPI()
@app.get("/demo/")
async def create_item():
return {"demo": "hello world"}
if __name__ == "__main__":
import uvicorn
uvicorn.run(
app='main:app',
host="127.0.0.1",
reload=True,
port=8000,
log_config="./uvicorn_config.json"
)